Cellulose ether and process of making same



Patented Aug. 12,

UNITED STATES 1,505,043 PATENT OFFICE,

Lnon nnmnrnnn, or vmmu, A'Us'ram.

'cnLLnLosE mnna AND Pnocnss or mama sum No Drawing. Appllcationnled June 10,

I citizen of the Republic of Poland, residing at Vienna, Austria, have invented certain new and useful Improvements in Cellulose Ether and Processes of Making Same, of which the following is a specification.

For many technical purposes, such for example as for the making of artificial filaments and threads (including artificial silk), finishing materials, and the like, those ethyl, derivatives of cellulose and, its conversion products which are insoluble in water at room'" temperature or only swell slightly therein, but which swell in colder water. or even whichdissolve in very cold water, have been demonstrated to be valuable in many cases.

Such ethyl derivatives of cellulose and a,- process of making the same, form theobject of the present invention.

I have made the discovery that alkyl ethers of cellulose of excellent quality and in good yields,- can be produced, starting from alkyl cellulose (such, for example as ethyl cellulose) which are soluble in water at room temperature, or from reaction mixtures which contain such alkyl celluloses,

* by converting these alkyl celluloses which are soluble in water at room temperature into alkyl cellulose s which are not soluble in water at 16 (3., but which swell or are soluble in colder -water, parti6ularly below 10 'C., by so calculating the content of the reaction mixture in alkali that the quantity :of alkali amounts to not less than one-tenth and not more than one-fourth of the, quantity of thewater present in the reaction mixture.

Thefollowing examples may represent th proportions (the parts are by weight) I for example a reaction mixture contains 2 to 5 parts of'water to one part (calculated as the dry substance) of an ethyl cellulose soluble in-water at 16 .C., then according to the present invention the caustic-alkali content of the reaction mixture should be between 0.3 and 1 part. If for example the reaction mixture contains 5 to 10 parts of water to 1 part of the ethyl cellulose s0luble in water at 16 C. (calculated as the dry substance), then according. to the present invention not less. than 0.75 and not more than 2.5 parts of caustic alkali are to be 1922. serial'no; 507,430.,

example the reaction mixture contains 10 to 20 parts of water to 1 part of the ethyl cellulose soluble in water at 16 C. (calculated as the dry substance), then the reaction mixture is to contain not less than 2 and not more than 5 parts of caustic alkali.

For executing the process, in the fi place, an ethyl ether of cellulose or of a conversion product of the same, soluble in water at 16 C. is made, which for example may be accomplished byethylation of alkali cellulose or a conversion product or derivative of cellulose or the. like soluble in alkali by means of diethyl sulfate or an ethyl halid, in known manner. (See for example, Austrian Patent.No. 78,217, Ex-

amples I to VI and Example XI and thecorresponding examples in U. S. Patent 1,188 ,37 6.) This ethyl cellulose, soluble in water at 16 (3., may then be isolated and treated with water and caustic alkali withinafter a previous elimination of a part of the water present in it, has so much caustic alkali (in'solution or in solid form) added to it, as is needed to give a proportion of water to caustic alkali (taking into consideration any caustic alkali already presept in reaction mixture which was not used up in the primary reaction) which lies within the quantitative limits stated above. Then (in either of the two cases) an ethylating' agent (for example, diethyl sulfate or an ethyl lialid) is added, and the mixture heated preferabl to 40-150 C., for say 2-24 hours. (If di-et yl sulphate is used as ethylatmg agent, the'temperature may preferably be between about 40 and (1., whilst, if an ethyl halide. is used the temperature may preferably be between and 150 C.)

process, the -crude reaction 0th cases the caustic alkali as well as the 'ethylatin'g agent may beadded all at oncepreliminariliy with water or not, and either as it is, or after previous neutralization or acidification, on a filtering apparatus for example a filter press, a suction filter, a straining cloth a centrifuge or the like, and then washlng out the precipitate with water As the cellulose ethers are insoluble in water at 16 (3., water at this temperature or larly in water at below 10 C. Whether it merely 'swells in cold water or dissolves, depends on the proportions of the water to the caustic alkali, as will appear from. the

' following examples, which are given for the purpose of illustration, and not as defining the scope of the invention.

Example I.

- 2400 parts of an aqueous alkaline solution of a cellulose derivative or'conversion product soluble in alkaliare taken. This may be for example the cellulose xanthogenate described in Austrian Patent 82,837 or French Patent No. 474,793 or British Patent No. 14,339 of 1914 or U. S. Patent 1,379,351; or a purified viscose made according to an older process, for example a viscose purified by adding salts, or salts and acids, al-

' cohols or the like; or a cellulose hydrate made by treatment of cellulose with hot alkali solution or with Schweizers reagent and subsequent precipitation, or by heating the cellulose hydrate made from viscose according to the process of Gseg'man Patent No. 155,745; or a hydrocellulo made by treating cellulose with strong sulfuric acid (amyloid, acid-cellulose, Guignet cellulose and, the like) or. another cellulose hydrate or the like. Such solution should contain 200 parts of the original cellulose (a quantitative determination of the content of cellusolution is slightly warmed, and then is treated while stirring with 600 parts of di- 6 ethyl sulfate added in successive small portions, or as. a slow stream. The addition of the latter may require 1 to 2 hours. Then if necessary water bath.

- The preferred tem ratures in thisprocit is heated very slowly on the ess during and after he addition of the di- A thin paste results.

"been used.

ethyl sulfate, may, for example, be as follows: i

1) recs cenlfgrade.

Temperature of the water bath 30 Temperature of the solution of the cellulose derivative or conversion product Durin this period of time the .whole of the diet yl sulfate has been incorporated with the reaction mixture.

Degrees centlgrnde.

Temperature after 2 hours 15 minutes Temperature after 2 hours 30 minutes" 47 I Temperature after 2 hours 45 minutes 48 Temperature after 3 hours 51 Temperature after 3 hours 15 minutes 55 Temperature after 3 hours 30 minutes 53 Temperature after 3 hours 45 minutes 50 The final reaction mixture (about 3,000 parts by weight) now forms a viscous, salve1ike mass, which besides by-products contains the ethyl'ether of cellulose, soluble in water at 16 C. This reaction mixture is now rubbed or kneaded up with 36 parts of pulverized caustic soda, and then if necessary, strained, whereupon 294 parts of diethyl sulfate are added, and it 1s heated on the water bath with forcible stirring. After the reaction mixture has reached about 80 to 90 C., the reaction is ended. A rather thin paste results, which is cooled to C. and rubbed or kneaded or stirred with 72 parts of pulverized caustic soda. Then 294 parts of diethyl sulfate are again added,

and it is heated on the water bath. The reaction again occurs between and C. Thispaste is again cpoled to 60 C., 72 parts of pulverized caustic sode are again stirred in, whereupon 294 parts of diethyl sulfate are again added, and the mixture is heated on the water bath. The reaction again occurs between 70 and90 C., and leads to a thin paste. Now the addition of 72 arts of caustic soda and 294 parts of dietl fyl sulfate, with subsequent heating, is repeated twice more in the same manner, whereupon the reaction is ended. Altogether then 324 parts of caustic soda and 1470 parts of diethyl sulfate have The isolation of the finished cellulose other is accomplished by diluting the reac tion mlxture with water, bringing it upon a filtering apparatus, and washing with water dilute sulfuric or hydrochloric acid, again laced on a filtering apparatus, and washed ee from acid with water at room temperature, and either dried in vacuo or in the air. After comminution, a white powder results, which is soluble in water at 1 to 5 C. upon kneading. This solution however congeals at 16 C. The body is insolublein water at 16 (1., or above, and does,not swell therein. The body is further soluble in a whole series of volatile solvents such as for example alcohol, alcohol-benzol mixture, chloroform, chloroform-alcohol mixture, amyl acetate, glacial acetic acid, and the like. The solutions dry to a transparent, flexible skin. Such skins. are insoluble in water at 16 (3., but swell in water at 8 to 10 (1., without decomposing, and dissolve in water at about 4 C. and below.

I The yield obtained is about 100%, calculated on the weight of the'cellulose employed as starting material.

The combustion of a sampleof an ethyl ether of cellulose prepared according to this example, dried to constant wei ht, and containing 0.5% of ash, showedt at the body (calculated for matter free from ash) contained: 54.26% C and 8.46% H. Calculated for 2400 parts of initial solution as in Example I are treated exactly as in Example I, with 600iparts of diethyl sulfate to produce an ethyl cellulose soluble in water at 16. Assoon as this is formed, the salvelike reaction mass is slowly incorporated with 325 parts of pulverized caustic soda, preferably with cooling and continuous lmeading. After incorporation of the whole of the caustic soda, a whitish. salve-like paste results. It is treated with 350 parts of diethyl sulfate and heated on a water bath. The reaction occurs between 70 and 90 C. The resulting reaction paste is cooled to-60 (1., again treated with 350 .parts of diethyl sulfate and heated on the waterbath. The reaction again occurs at between and C. A rather thin paste results. This paste is still twice more treated in the same manner with 350 parts each time of diethyl sulfate, with heating, Alto- After drying and comminution, the ethyl cellulose consists of a white powder, which is not solublein water at 16, swells but little in water at 9 to 10, and only shows a distinct swelling in water when the same is at 5 to 8 0., or colder. In water below 5 the swelling is very distinct but without a distinct solution occurring. The ethyl cellulose is, like that previously described. soluble in-a whole series of volatile solvents (as given in Example I). On drying its solutions, a transparent, flexible fihn remains, which is only slightly swelled in water at 9 to 10. and only in water at between 5 and 8 or colder, shows distinct swelling. In water at 1 (1., it swells very strongly, and the destruction of the film results.

The formula represented by this example gives a yield of about 100% calculatedon the weight of the cellulose employed as starting material.

The combustion. of a sample of a pr'oduct made in accordance with this example, dried to constant weight, and containing 0.61% of ash, showed that the substance (calculated for matter free f m ash) contained: 54.91% C and 8.32%

Calculated for The determination of the ethoxylv number showed that 26.3% of the body consisted of ethyl groups. p

Exzmnpk I l I 2400 partsof the initial solution used in Examples I and II are converted as in Examples I and II, by treatment with 6008,00 parts of ethyl sulfate. to produce an ethyl ether soluble in water at 16 C. After the heating which occurs similarly to that given in the two previously described examples, a

whitish, cheesy paste results. which contains the ethyl cellulose soluble in water at 16. Into the reaction paste,,cooled to 16 (3., are

rubbed 62 parts of pulverized caustic-soda,

whereupon the temperature rises to 23 C. The white. cheesy mass formed is now treated with 260 parts of diethyl sulfate and slightly heated on the water bath. The resulting thick paste is cooled to 60 and treated with 62 parts of pulverized caustic soda with kneading. whereupon again 260 parts of diethyl sulfate are added, and the reaction mixture heated-on the water bath. The reaction occurs at about 90 C. The resulting cheesy-flocculent paste is cooled to 30 0., whereupon itis slowly incorporated with 315 parts of-pulverized caustic soda in small portions with kneading. The temperature 1 during the rubbing in of the caustic soda rises to 45 G. Then three times more in the same manner, 260 parts a of diethyl sulfate are added and it is heated nor in water below 10.

' amplesItoIII. 4

on the water bath. Altogether 439 arts of caustic soda and 1300 parts of diet yl sulfate are added.

The isolation of the finished ethyl cellu- 6 lose is accomplished in the same manner as 1 and 5. The ethyl cellulose is, as that described previously, soluble in a whole series of volatile solvents. Its solution leaves behind a transparent, flexible film, which easily swells only in very cold water (for example 1 to '5 (1), without dissolving or disintegrating,

The yield obtained is about 100% calculated on the weight of the cellulose employed as starting material.

The combustion of a sample of an ethyl cellulose prepared according to this example, dried to constant weight, and containing 0.54% of ash, showed that the body (calculated for matter free from ash) contained:

53.96% C and 8.57% H. Calculated for Mc Hamomcamossom. 54.23% c, 8.09% H.

The determination of the ethoxyl number showed that 24.4% of-the substance consisted of ethyl groups.

p Example IV.

2400 parts of the initial solution as in Examples I to III are treated with 600 parts of diethyl sulfate, and converted into the cellulose ether soluble in water at 16.

40 After the heating, which occurs similarly to that in the previous examples, a whitish, ,salve-like mass results, which contains the ethyl cellulose soluble in water 'at 16. Then, at C., .100 parts of caustic soda 45 are incorporated with the mass.' Into the salve-likemass formed, 200 to 360 parts of diethyl sulfate arethen stirred, and it is heated on the water bath. The reaction occurs between 70 and 90 C; 100 parts of pulverized caustic soda are stirred into the resulting mass while at a temperature of about 80 G. Then another 200 to 360 parts of diethyl sulfate are added, and it is heated on. the water "bath, The reaction occurs again at between 70 and 90 C. The resulting paste is still three times more treated in the same manner with 100 parts offpulverized caustic soda and with 200 to 360 parts ofv diethyl sulfate, while in a heated state. Altogether 500 parts of caustic soda and 1000 tov 1800 parts of diethyl sulfate are added.

The isolation of the ethyl cellulose formed is carried out in the same manner as in Ex- 7 3 (1). The film becomes stretchy therein,

without dissolving or disintegrating.

The yield obtained is about 100% calculated on the weight of the cellulose employed as starting material.

The combustion of a sample of a product made in accordance with this example, dried .to constant weight, and containing 0.44%

' of ash, showed that the substance (calculated for matter free from ash) contained: 54.30% C and 8.48% H. Calculated for The determination of the ethoxyl number showed that 23.99% of the substance consisted of ethyl groups.

Example V.

2400 parts of the initial solution as in Examples'I to IV are treated with 600 to 720 parts of diethyl sulfate exactly as in Examples I to IV. The resultin reaction paste, which contains the ethyl ce lulose soluble in water at 16, possibly after a. previous straining, is evaporated either in an open vessel (evaporating dish or the like) .or invacuo (for example in a vacuum kneader) to 1080 to 1200 parts by weight, being constantly kneaded. Then the resulting mass, which may be rubbed to pieces, if necessary, is comminuted and rubbed up, whereupon 120 to 150 parts ofpulverized caustic soda are rubbed in small portions, preferably with cooling, until complete 'homogeneityis secured. The'resulting mass is now treated with 165' parts of diethyl sulfate and heated with stirring or kneading on the water bath. The heatin is'so conducted that the temperature whlch may be about 20 C. at the beginnin rises to 60 C. after about 40 minutes. tween 60 and 70, the reaction occurs, and there results a soft doughy mass or a soft cheesy paste- The mass is then cooled to 30 0., again treated with 165 pam of diethyl sulfate and again slowly heated on the water bath. The reaction again occurs at (SO-70 C.

The isolation of the finished ethyl cellulose is efiected as in the revious examples. It is after drying, a white powder which, like the previous ones, is soluble in many organic solvents. The solution leaves behind a transparent'andflexible film, which swells .easily only in practically ice-cold water (for example 1 C.) and becomes stretchy therein, without dis solving .or disthe body (calculated for matter free from ash) contained: 55.72% C and 8.85% H.

Calculated for of cellulose is carried out,

moan om-uoan oaacine; c, s.44%-H.

The determination of the ethoxyl number showed that 28.7% of the body consisted of ethyl groups. I

. Ewample VI.

24001parts ofinitial solution as in Example incorporated with 500 to 1000 parts of a 30% caustic soda solution), placed in an autoclave, 800 to 900 parts of ethyl chloride are added, and the reacting mixture is kept at a temperature of .801 20 C. for 4 to 12 hours. The material in the autoclave .is either stirred, or the autoclave kept in motion during the reaction. After the autoclave has cooled, the mass is,-with cooling, rubbed up, or kneaded, or stirred with 320 to 400 parts of pulverized caustic soda, and placed again in the autoclave. Then 512- 640 parts of ethyl chloride are added, the reaction mass heated to 100-130 0., and kept at this temperature for 4 to 14 hours.

The isolation of the finished ethyl ether for example, in the same manner as in the foregoing examples.

'After drying and commi ution,-the ethyl cellulose represents a piil verulent mass,

I which is insoluble in water at 16 0., but

. ticularly below 5 C.

shows by itself, or in the form of a film, a distinct swelling in water below 10 It is soluble in a whole series of volatile organic solventsJas given in Example I). v

\ Example VII.

200 parts of sulfite-cellulosel-are impregnated, with 1000 parts of a 25-30% caustic soda solution and, preferably after standing for 1 to 3 days, placed in an autoclave. Then 400 to 480 parts of ethyl chloride are cured. The resulting mass is now placed back in the autoclave, 192 to 256 parts of ethyl chlpride are added, andthe mass heated (prepared in accordance employed, for examp are (optionally after having been 0., parto 100 to 140 C. and kept at this temperature for5 to 12 hours.

The isolation of the finished ethyl cellulose is effected as in the previous exam les. It is, after drying a fiulverulent or occulent substance, whic l e the previous ones, is

soluble in many organic solvents. Its solutions leave behind films whichare insol-- uble in water at 16 0., but'which swell up in water below 10 0., particularly below 5 C. (u

Instead of di-ethyl sulphate or .ethyl chloride other suitable alklylating agents may be e di-methyl sulphate, methyl chlorlde, ethyl iodide, ethyl bromide, or their higher homologues.

The process may also be.carried out in such a manner that an alkyl ether of a cellulosic body soluble in water at 16 C'., is prepared by means of one alkylating agent, whilst the conversion of this ether into the higher alkylated cellulose ether may be effected by an other alkylating agent. B

using in the first stage and second stage di ferent alkylating agents, for example in the first stage an inorganic meth l ester'and in the second an inorganic ethy ester, and observing the proportions underlying the present application, one may obtain mixed al 1 ethers of cellulosic bodies properties described herein.

Owing 'to their property of swellin and even dissolving in cold water, w being insoluble in water. at ture, the herein described room termperaalkyl ethers of cellulosic bodies are suitable for the production of artlcles that have to be impre ated or incorporated or'otherwise combine with substances soluble in water, for example dyes. Thus, the herein described alkyl ethers of cellulose are especially suitable for the manufacturing of artificial filaments and threads, such as artificial silk, artificial hair and the like.-

The herein described alkyl ethers of cellulosic bodies are furthermore suitable for the production of all such articles as must be insoluble in water at room temperature but as are preferably and more economically produced in aqueous solutions, for instance photographicy emulsions, photographic layers sensitive to light, coatings of all kinds, dressings, fillings and finishings for textiles, paper, leather and the like, sizing for spun goods, printing agents and compositions, thickening agents for the same, agents for fixing pigments, adhesives, cements, glues, adhesive pastes, sizes for 'paper, photographic lacquers, varnishes and paints for general purposes,

artificial leather, book cloth, etc.

-For the aforesaid uses, the herein described alkyl ethers of cellulosic bodies may membranes,

lbe combined with water-soluble cellulose de'riyatives (such as viscose, cuprammodisplaying t e k,

ilst

nium cellulose and the like) or with waterinsoluble cellulose derivatives (such as nitro-celluloses, acetyl-celluloses, formylcelluloses and the like), or with other water-insoluble or water-soluble colloids, binding agents, thickening agents (such as starch, dextrine, British gum, glue (gelatine), albumen, casein, tragasol, gum tragacanth', caoutchouc, guttapercha, balata, resins of cellulose or. its conversion products,

which are insoluble in water at 16 C. and above, but are afiected in water at'some temperature below 16- C., which comprises treating an ethyl derivative of a cellulosic body soluble in water at 16 C., with a caustic alkali and an ethylating agent, while the content by weight of the reaction -mixture in caustic alkali is not less than one-tenth and not more=than one-fourth of the quantity of the water contained in the reaction mass. I

2. Process ,for -makingethyl derivatives of cellulose or its conversion products, which are insoluble in water at'16 C. and

above, but are affected in water at some temperature below 16 0;, which comprises treating a reaction mixture from the production of ethyl cellulose which is soluble in water at 16 'C.', and containing such an ethyl cellulose, water, and other reaction products soluble in water at 16 C., with a caustic alkali and an ethylating agent, while the content by weight of thereaction mixture in caustic alkali is not less'than one-tenth andnot more than one-fourth of the quantity of the water contained the reaction mass.

3. In the process according to claim 1, the improvement which comprises treating with an ethylating agent, a reaction mixture containmg the ethyl ether of acellu- -losic body soluble in water at 16 (3., such mixture containing for each part by weight of dry ethyl cellulose soluble in water at 16 C., 2 to 5 parts by weight'of water and between 0.3 and 1 part by weight of caustic alkali.

' 4. In the process according to claim 1, the improvement which comprises treating with an ethylating agent, a reaction mixture containing an ethyl ether of a cellulosic body, which is soluble in water at 16 (1., which reaction mixture contains to each part by weight of dry ethyl cellulose soluble in water at 16 (1., from 5 to 10 parts by weight of water and not less than 0.75 and not more than 2.5 parts by weight of caustic alkali.

5. In the process according to claim 1, the improvement which comprises treating with an ethylating .agent, a reaction mixture containing an ethyl ether of a cellulosic body, which is soluble in water at 16 (1., and containing such an ethyl cellulose, water,-and other reaction products.

6. In the process of claim 1, the improvement which com rises adding the caustic alkali and the ct ylating agent in successive portions, while maintaining the stated 86 ratio between water and caustic alkali.

7. A process of making alkyl derivatives of cellulose or its conversion products, which are insoluble in water at 16 C. and above, but are affected in water at some temperature below 16 0., which comprises treating an alkyl derivative of a cellulose body soluble in water at 16 (3., with a caustic alkali and an alkylating agent, while the content by weight of the reaction mix- "ture in caustic alkali is 'not less than onetenth and not more than one-fourth of the quantity of the water contained in the reaction mm- 8, A process for making alkyl derivatives of cellulose or its conversion products, .WhlCh are insoluble in water at 16 C. and above, but are afiected in water below about 10. C., which comprises treating a reaction mixture from the production of al 1 cellulose which is soluble in water at 16 and containing such an alkyl cellulose, water, and other reaction products soluble in water at 16 .C., with a caustic alkali and an alkylating agent, while the content by weight of the reaction mixture in caustic alkal' is not less than one-tenth and not more t an one-fourth of the quantity of the water contained in the reaction mass.

9. In the process according to claim 1, the improvement which comprises treating with an ethylating a nt, a reaction mixture containing anet yl ether of a'cellulosic body, which is soluble in water at 16 C., which reaction mixture contains to each part by weight of dry ethyl cellulose soluble in water at 16 C., from 10 to 20 parts by weight of water and not less than 2 and not more than 5 parts by weight of caustic alkali. p

10. Alkyl ethers of cellulosic bodies, vwhich are insoluble in water at above '16 .C.,.but which swell in water below about 10 C., and which are soluble in many organic solvents.

. 11. Alkyl ethers of cellulosic bodies, insoluble in water at 16 C. and above, but capable of substantially swelling in water at from 5 to 8 C. 12. Alkyl ethers of cellulosic bodies, insoluble in water at 10 C. and above, but capable of substantially swelling in water at froml to 5 C. I

13. Alkyl ethers of cellulosic bodies, which are insoluble in water at 16 C., and above, such ethers swelling substantially in water at some temperature substantially below 16 C.

14. Ethyl ethers of cellulosic bodies, which are insoluble in water at above 16 C., but which swell in water below about 10 (1., and which are soluble in many organic solvents. l5. Ethyl ethers of cellulosic bodies, insoluble in water at 16 C., and above but capable of substantially swelling inwater at from5to8 C.- 1

16. Ethyl ethers of'cellulosic bodies, insoluble in water at 10 C. and above, but capable of substantially swelling in water at from 1 to 5 C. 4

17. Ethyl ethers of cellulosic bodies, which are insoluble in water at .16" C. and above,jsuch ethers swelling substantially in water at some te low 16 'C. 18. An ethyl perat-ure substantially be- I ether of acellulosic body,- -which is insoluble in water at 16 (1,- and above, but which is somewhat soluble in Water at temperatures of, about 0 to 5 C., which product can be made by treatment of an ethyl derivative of a cellulosic body soluble in Water at 16 (1, either alone or in the form of reaction mixtures which contain such an ethyl cellulose, with caustic alkali and an ethylating reagent in the presence of a quantity of caustic alkali which amounts to-not less than one-tenth and not more than one-fourth of the quantity of the Water contained in the reaction mixture.

19. An ethyl ether of a cellulosic body, which is insoluble in water at 16 0., and

above, but which swell perceptibly in water a than one-tenth andnot more than onefourth .of the quantity of the water contained in the reaction mixture.

In testimonty whereof I afiix my signature in presence-o .two witnesses.

LEON VLILIENFELD.

Witnesses:

CARL Sommmn, CARL JERESIZOK. 

